Video security cameras are available for use by homeowners and business people for viewing selected premises areas on a TV monitor. The most basic system of this type comprises a single video camera which has a video signal connected through a cable to a television monitor at a different location. With this combination a user can continuously monitor a particular area. For most applications, the typical system has a dedicated monitor, usually black and white, for monitoring one area by use of the video camera. A homeowner can use such a dedicated video monitor but it is often inconvenient and obtrusive to have such a monitor in the home. Some consumer television sets have a second video input for receiving baseband video signals and these sets can be used both for conventional viewing and to monitor the video signal from a security camera. However, many consumer television sets have only one input.
It is frequently desirable for persons who need video monitoring, both in homes and businesses, to have a group of such video monitors. A homeowner may want to monitor various exterior areas and interior rooms for purposes of security. Security video monitors are available which have inputs for multiple video sources. These monitors can be set to sequentially show the signals being received from each of the video cameras or to continuously monitor any one camera. While this may be acceptable to the business person who has an employee, such as a security guard, for continuously monitoring the entire business premises, a homeowner generally does not spend an extended period of time at one location monitoring a security television monitor. Further, for home use, such monitors can be obtrusive and expensive. It would be desirable for a homeowner to monitor a security camera through his usual television set, but such sets rarely have more than one extra input terminal, and many have no extra input terminal. Therefore, it is generally not possible to monitor more than one security camera through a conventional television set.
In view of these limitations, there exists a need for an electronic apparatus to enable a user, at either a home or a business, to monitor a plurality of local video cameras through a conventional television set.